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Genetics/Brachydactyly type b

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I knew a family as a child in which the two boys of the family had inherited what seems to have been BTB. Their fingers were so short that they seemed to be missing the last two phalanges of each finger. There were no extra fingers, nor absent or fused fingers. I do not recall any webbing, but it was long ago and I might not recall completely. Both boys were on the short side of normal and very compactly, strongly built, but normal. The mother of the family shared this physique.

The girls of the family, and their father, were all of normal to tall height, with normal, slender, long fingers. I believe they were of Scandinavian descent, probably Swedish. The mother was an orphan.

1. All the people of this family appeared to be of normal intelligence. Are there other disabilities associated with this syndrome?
2. Would the girls of this family have been carriers of this syndrome?

Thanks for your help in understanding this.

Answer
Hi
If the diagnosis is brachydactyly type B, this syndrome is autosomal dominant. What this means is that, carrying one allele is enough to express the syndromes. Only recessive traits require two copies to express, while those who carry one copy are carriers. So if the daughters are normal, logically they are not carriers.

Based on literature this is a rare syndrome, and associated anomalies are confined to hands and feet. No report of mental affliction is reported. It is caused by mutation of a gene ROR2 in chromosome 9q. Other types of mutations are known to lead to other conditions which can be recessive. Besides, there could be what we call "linkage" associated with this gene- which means that this gene might "travel" with specific gene and gets transmitted to next generation together.

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Thanemozhi Natarajan

Expertise

Answers in Genetics, genomics, cytogenetics of syndromes, congenital anomalies, cancer, clinical genomics and interpretation of omics data.

Experience

More than 10 years. Doctoral research thesis on Congenital anomalies and cytogenetics, Recurrent reproductive failure and chromosomal abnormalities. Postdoctoral experience in Breast cancer research. Current: Clinical Genomics and Pharmacogenomics.

Organizations
Academic

Publications
Cancer Cell International, Cancer Epidemiology Biomarkers and Prevention, Breast cancer research and treatment, Indian Journal of Pediatrics, BMC Proceedings, Pharmacogenetics and Genomics, Human Molecular Genetics, Frontiers in Genetics, Cancer Biomarkers.

Education/Credentials
PhD Biomedical Genetics

Awards and Honors
University Grants Commission Award for pursuing PhD level research (India); Travel awards to attend conferences.

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Post doctoral experience Cancer research, molecular epidemiology Current: Clininical Genomics and Pharmacogenomics

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